If boulders could talk

“Where do you come from?” is a common question between delegates at conferences, and the 22nd Pacific Science Congress is no different. But it’s a not a question that you would usually associate with boulders.

Where are you from? (Credit: US Geological Survey)

Coastal boulders move only when there is a major event such as a tsunami or storm surge, so, if you know their size and density, you can work out how much energy is required, and therefore the power of the tsunami or storm surge, to unceremoniously move it.

That’s why, as Adam Switzer, from the tectonics group at the Earth Observatory of Singapore, explained in a session this afternoon, researchers need to know where boulders washing up on coastlines or being hurled further inland have come from.

But researchers studying an event after the fact rarely know boulders’ original positions. Enter GeoBoulder, an online portal that aims to collate information about coastal boulders all over the world – and make it available for everyone.

The idea is that users will use a simple form to upload information about boulders in their area or that they have studied. This will help researchers study events in the immediate aftermath, as well building up a picture of how boulders move during tsunamis and storms that can be used to reconstruct past events.

But how does this help those living in coastal areas vulnerable to tsunamis and storms? Non-research applications haven’t been a priority, said Switzer but he can envisage uses for local authorities aiming to mitigate disasters.

“If you’ve got a seawall constructed from the same kind of boulders that were moved by a tsunami up the coast, you could use it to work out how far those boulders could travel in a similar event,” he said.